Trump literally got into a heated exchange with the Danish representative. https://www.yahoo.com/news/trump-had-horrendous-call-danish-193412504.html He is quite serious, because he's all into the sort of government that could shift into the Project 2025 dictatorship he wants, and that's imperialism. He's setting up the ground for the fake outrage that will fuel actions that would otherwise be indefensible. They will still be indefensible, but doing it overtime allows him to prune his critics from any position of influence.
The consolidation of his power is probably true, but even in that context I'd say demonizing Denmark is probably a swing and a miss. I still say there's no plausible chain of events where this ends with Greenland as part of the United States.